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Python - Coggle Diagram

- - - - a variable named "message"
      - the value is the text “Hello Python world!”
    - - contain only letters, numbers, and underscores. They can start with a letter or an underscore, but not with a number. For instance, you can call a variable message_1 but not 1_message.
      - Spaces are not allowed in variable names, but underscores can be used to separate words in variable names. For example, greeting_message works, but "greeting message" will cause errors.
      - Avoid using Python keywords and function names as variable names (See “Python Keywords and Built-in Functions” on page 489.)
      - Variable names should be short but descriptive.
      - Be careful when using the lowercase letter l and the uppercase letter O because they could be confused with the numbers 1 and 0.
    - - The Python variables you’re using at this point should be lowercase. You won’t get errors if you use uppercase letters, but it’s a good idea to avoid using them for now.
  - - - Ex: name = "Ada Lovelace"
        print(name.lower())
        => ada lovelace
      - The lower() method is particularly useful for storing data
        you’ll convert strings to lowercase before storing them
    - - A string is simply a series of characters.
    - - Ex: name = "Ada Lovelace"
        print(name.upper())
        => ADA LOVELACE
    - - Ex: name = "ada lovelace"
        print(name.title())
        => Ada Lovelace
      - title() displays each word in titlecase, where each word begins with a capital letter
    - - concatenation
        
        This method of combining strings
        
        Ex: first_name = "ada"
        last_name = "lovelace"
        full_name = first_name + " " + last_name
        print(full_name)
        print("Hello, " + full_name.title() + "!")
        
        variable: message = "Hello, " + full_name.title() + "!"
        print(message)
      - Combining
        
        uses the plus symbol (+) to combine strings
    - - Tabs
        
        Ex: print("Python")
        Python
        print("\tPython")
        ------Python
      - Newlines
        
        Ex: print("Languages:\nPython\nC\nJavaScript")
        Languages:
        Python
        C
        JavaScript
      - Combine tabs and newlines in a single string
        
        Ex: print("Languages:\n\tPython\n\tC\n\tJavaScript")
        Languages:
        ----Python
        ----C
        ----JavaScript
    - - favorite_language = ' python '
        favorite_language.rstrip()
        ' python'
        favorite_language.lstrip()
        'python '
        favorite_language.strip()
        'python'
        
        rstrip(): ensure that no whitespace exists at the right end of a string
        
        lstrip: ensure that no whitespace exists at the left side of a string
        
        strip(): strip whitespace from both sides at once
    - - A syntax error occurs when Python doesn’t recognize a section of your program as valid Python code
  - - - the hash mark (#) indicates a comment
  - - - You can add (+), subtract (-), multiply (*), and divide (/) integers in Python, two asterisks represent exponents
      - 2 + 3 -> 5
        3 - 2 -> 1
        2 * 3 -> 6
        3 / 2 -> 1.5
      - Dấu mũ: 2 sao
      - When you use integers within strings, you need to specify explicitly that you want Python to use the integer as a string of characters.
        
        age = 23
        message = "Happy " + str(age) + "rd Birthday!"
        print(message)
        => Happy 23rd Birthday!
    - - any number with a decimal point a float
  - - - Don’t try to write perfect code; write code that works, and then decide whether to improve your code for that project or move on to something new.
- - - - A list is a collection of items in a particular order
      - letters (alphabet), digits (0-9), or names.
      - Ex: bicycles = ['trek', 'cannondale', 'redline', 'specialized']
        
        square brackets ([]) indicate a list
        
        individual elements in the list are separated by commas (,).
      - Accessing Elements in a List
        
        telling Python the position, or index, of the item desired.
        
        Index Positions Start at 0, Not 1
        
        index -1 -> the last item
        
        Ex: print(bicycles[0])
        -> trek
        
        Ex: print(bicycles[0].title())
        -> Trek
      - Using Individual Values from a List
        
        use concatenation
        
        Ex: message = "My first bicycle was a " + bicycles[0].title() + "." print(message)
    - - Modifying Elements
        
        Ex: motorcycles = ['honda', 'yamaha', 'suzuki']
        print(motorcycles)
        =>> ['honda', 'yamaha', 'suzuki']
        motorcycles[0] = 'ducati'
        print(motorcycles)
        =>> ['ducati', 'yamaha', 'suzuki']
      - Adding Elements
        
        Appending Elements
        
        the new element is added to the end of the list
        
        Ex: motorcycles.append('ducati')
        print(motorcycles)
        =>> ['honda', 'yamaha', 'suzuki', 'ducati']
        
        you can start with an empty list and then add items to the list using a series of append() statements
        
        Ex: motorcycles = []
        motorcycles.append('honda')
        motorcycles.append('yamaha')
        motorcycles.append('suzuki')
        print(motorcycles)
        =>> ['honda', 'yamaha', 'suzuki']
        
        Building lists this way is very common, because you often won’t know the data your users want to store in a program until after the program is running.
        
        Inserting Elements
        
        The insert() method opens a space at position 0
        
        Ex: motorcycles.insert(0, 'ducati')
        print(motorcycles)
        =>> ['ducati', 'honda', 'yamaha', 'suzuki']
      - Removing Elements
        
        Using the del Statement
        
        Ex: motorcycles = ['honda', 'yamaha', 'suzuki']
        print(motorcycles)
        =>>['honda', 'yamaha', 'suzuki']
        del motorcycles[0]
        print(motorcycles)
        =>> ['yamaha', 'suzuki']
        
        You can remove an item from any position in a list
        
        you can no longer access the value that was removed from the list after the del statement is used.
        
        Using the pop() Method
        
        The pop() method removes the last item in a list, but it lets you work with that item after removing it
        
        Ex: umotorcycles = ['honda', 'yamaha', 'suzuki']
        print(motorcycles)
        =>> ['honda', 'yamaha', 'suzuki']
        popped_motorcycle = motorcycles.pop()
        print(motorcycles)
        =>> ['honda', 'yamaha']
        print(popped_motorcycle)
        =>> suzuki
        
        the value 'suzuki' was removed from the end of the list and is now stored in the variable popped_motorcycle
        
        Popping Items from any Position
        
        motorcycles = ['honda', 'yamaha', 'suzuki']
        first_owned = motorcycles.pop(0)
        print('The first motorcycle I owned was a ' + first_owned.title() + '.')
        =>> The first motorcycle I owned was a Honda.
        
        when you want to delete an item from a list and not use that item in any way, use the del statement; if you want to use an item as you remove it, use the pop() method.
        
        Removing an Item by Value
        
        If you only know the value of the item you want to remove, you can use the remove() method.
        
        Ex: motorcycles = ['honda', 'yamaha', 'suzuki', 'ducati']
        print(motorcycles)
        =>> ['honda', 'yamaha', 'suzuki', 'ducati']
        motorcycles.remove('ducati')
        print(motorcycles)
        =>> ['honda', 'yamaha', 'suzuki']
        
        the value 'ducati' has been removed from the list but is still stored in the variable "too_expensive"
        
        too_expensive = 'ducati'
        motorcycles.remove(too_expensive)
        print(motorcycles)
        print("\nA " + too_expensive.title() + " is too expensive for me.")
        =>> A Ducati is too expensive for me.
        
        The remove() method deletes only the first occurrence of the value you specify.
    - - Sorting a List Permanently
        
        Ex: cars = ['bmw', 'audi', 'toyota', 'subaru']
        cars.sort()
        print(cars)
        =>> ['audi', 'bmw', 'subaru', 'toyota']
        
        changes the order of the list permanently.
        
        The cars are now in alphabetical order, and we can never revert to the original order:
        
        Ex: cars.sort(reverse=True)
        print(cars)
        =>> ['toyota', 'subaru', 'bmw', 'audi']
      - Sorting a List Temporarily
        
        To maintain the original order of a list but present it in a sorted order, you can use the sorted() function
        
        print(cars): ['bmw', 'audi', 'toyota', 'subaru']
        print(sorted(cars)): ['audi', 'bmw', 'subaru', 'toyota']
        print(cars): ['bmw', 'audi', 'toyota', 'subaru']
        
        The sorted() function can also accept a reverse=True argument if you want to display a list in reverse alphabetical order.
        Ex: print(sorted(travel, reverse=True))
        
        Note: Sorting a list alphabetically is a bit more complicated when all the values are not in lowercase.
      - Printing a List in Reverse Order
        
        To reverse the original order of a list, you can use the reverse() method.
        
        cars = ['bmw', 'audi', 'toyota', 'subaru']
        print(cars)
        =>> ['bmw', 'audi', 'toyota', 'subaru']
        cars.reverse()
        print(cars)
        =>> ['subaru', 'toyota', 'audi', 'bmw']
      - Finding the Length of a List
        
        Ex: cars = ['bmw', 'audi', 'toyota', 'subaru']
        len(cars)
        =>> 4
        
        Note: Python counts the items in a list starting with one, so you shouldn’t run into any off- by-one errors when determining the length of a list.
      - Avoiding Index Errors
        
        IndexError: list index out of range
        
        when you request the last item from an empty list
  - - - When you want to do the same action with every item in a list, you can use Python’s for loop.
      - magicians = ['alice', 'david', 'carolina']
        for magician in magicians:
        -------print(magician)
        =>> alice
        david
        carolina
        
        you can choose any name you want for the temporary variable that holds each value in the list.
        
        Avoiding Indentation Errors
        
        Forgetting to Indent
        
        IndentationError: expected an indented block
        
        forget to indent the second line
        
        If you expect to see a certain action repeated once for each item in a list and it’s executed only once, determine whether you need to simply indent a line or a group of lines.
        
        Indenting Unnecessarily
        
        IndentationError: unexpected indent
        
        Indenting Unnecessarily After the Loop
        
        If an action is repeated many times when it should be executed only once, determine whether you just need to unindent the code for that action.
        
        Forgetting the Colon (:) at the end of a for statement
      - printing a message to each name
        
        print(magician.title() + ", that was a great trick!")
        
        print("I can't wait to see your next trick, " + magician.title() + ".\n")
        
        The newline ("\n") inserts a blank line after each pass through the loop
      - Doing Something After a for Loop
        
        we place the thank you message after the for loop without indentation
    - - Using the range() Function
        
        for value in range(1,5):
        -----print(value)
        =>>
        1
        2
        3
        4
        
        range(1,5) prints only the numbers 1 through 4
        
        If your output is different than what you expect when you’re using range(), try adjusting your end value by 1.
      - Using range() to Make a List of Numbers
        
        numbers = list(range(1,6))
        print(numbers)
        =>> [1,2,3,4,5]
        
        skip numbers in a given range.
        
        even_numbers = list(range(2,11,2))
        print(even_numbers)
        =>> [2,4,6,8,10]
        
        how you might put the first 10 square numbers into a list:
        
        squares = []
        for value in range(1,11):
        square = value**2
        ------squares.append(square)
        ------print(squares)
        =>> [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
        
        squares = []
        for value in range(1,11):
        ------squares.append(value**2)
        print(squares)
        
        List Comprehensions
        
        squares = [value**2 for value in range(1,11)]
        print(squares)
      - Simple Statistics
        
        digits = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
        min(digits)
        0
        max(digits)
        9
        sum(digits)
        45
    - - Slicing a List
        
        players = ['charles', 'martina', 'michael', 'florence', 'eli'] print(players[0:3])
        =>> ['charles', 'martina', 'michael']
        
        To make a slice, you specify the index of the first and last elements you want to work with
        
        print(players[1:4])
        =>> ['martina', 'michael', 'florence']
        
        print(players[:4])
        =>> ['charles', 'martina', 'michael', 'florence']
        
        print(players[2:]): includes the end of a list.
        =>> ['michael', 'florence', 'eli']
        
        we want to output the last three players on the roster, we can use the slice players[-3:]
        print(players[-3:])
      - Looping Through a Slice
        
        players = ['charles', 'martina', 'michael', 'florence', 'eli']
        print("Here are the first three players on my team:")
        for player in players[:3]:
        -------print(player.title())
        =>>
        Here are the first three players on my team:
        Charles
        Martina
        Michael
      - Copying a List [:]
        
        my_foods = ['pizza', 'falafel', 'carrot cake']
        friend_foods = my_foods[:]
        print(my_foods)
        print(friend_foods)
        =>> ['pizza', 'falafel', 'carrot cake']
        
        we actually have two separate lists
        
        If we had simply set friend_foods = to my_foods, we would not produce two separate lists
    - - what is tuples?
        
        A tuple looks just like a list except you use parentheses instead of square brackets.
        
        Tuples allow to create a list of items that cannot change
      - dimensions = (200, 50)
        print(dimensions[0])
        print(dimensions[1])
        =>> 200
        50
        dimensions[0] = 250 (thay 200 = 250)
        =>> TypeError: 'tuple' object does not support item assignment
      - Looping Through All Values in a Tuple
        
        dimensions = (200, 50)
        for dimension in dimensions:
        -------print(dimension)
        =>> 200
        50
      - Writing over a Tuple
        
        if we wanted to change our dimensions, we could redefine the entire tuple
        
        dimensions = (200, 50)
        print("Original dimensions:")
        for dimension in dimensions:
        ------print(dimension)
        dimensions = (400, 100)
        print("\nModified dimensions:")
        for dimension in dimensions:
        ------print(dimension)
    - - Take the time to make your code as easy as possible to read
      - PEP 8, which instructs Python programmers on how to style their code
      - Indentation
        
        use four spaces per indentation level
      - Line Length
        
        each line should be less than 80 characters.
      - people who are working collaboratively almost always follow the PEP 8 guidelines
      - Blank Lines
        
        Blank lines won’t affect how your code runs, but they will affect the readability of your code
- - - - Checking for Equality (==)
        
        car = 'bmw'
        car == 'bmw'
        True
        
        car = 'audi'
        car == 'bmw'
        False
        
        two values with different capitalization are not considered equal
        car = 'Audi'
        car == 'audi' False
        
        car = 'Audi'
        car.lower() == 'audi'
        True
        
        The lower() function doesn’t change the value that was originally stored in car
        
        When some- one submits a new username, that new username is converted to lowercase and compared to the lowercase versions of all existing usernames
      - Checking for Inequality (!=)
        
        requested_topping = 'mushrooms'
        if requested_topping != 'anchovies':
        print("Hold the anchovies!")
        =>> Hold the anchovies!
        
        If these two values do not match, Python returns True and exe- cutes
        
        If the two values match, Python returns False and does not run the code following the if statement.
      - Numerical Comparisons
        
        age = 18
        age == 18
        True
        
        answer = 17
        if answer != 42:
        print("That is not the correct answer. Please try again!")
        =>> That is not the correct answer. Please try again!
        
        age = 19
        
        age < 21 True
        age <= 21 True
        age > 21 False
        age >= 21 False
      - Checking Multiple Conditions
        
        sometimes you might need two conditions to be True to take an action =>> and and or
        
        And
        
        age_0 = 22
        age_1 = 18
        
        (age_0 >= 21) and (age_1 >= 21)
        False
        
        Or
        
        age_0 = 22
        age_1 = 18
        
        (age_0 >= 21) or (age_1 >= 21) True
        
        age_0 = 18
        
        (age_0 >= 21) or (age_1 >= 21) False
      - Checking Whether a Value Is in a List/ not in a list
        
        check whether a list contains a certain value before taking an action.
        
        To find out whether a particular value is already in a list, use the key- word in.
        
        requested_toppings = ['mushrooms', 'onions', 'pineapple']
        
        'mushrooms' in requested_toppings
        
        True
        
        'pepperoni' in requested_toppings
        
        False
        
        to know if a value does not appear in a list
        
        banned_users = ['andrew', 'carolina', 'david']
        user = 'marie'
        if user not in banned_users:
        print(user.title() + ", you can post a response if you wish.")
      - Boolean Expressions
        
        A Boolean expression is just another name for a conditional test. A Boolean value is either True or False, just like the value of a conditional expression after it has been evaluated.
        
        Boolean values are often used to keep track of certain conditions
        
        whether a game is running or whether a user can edit certain content on a website:
        game_active = True
        can_edit = False
    - - one test and one action
        
        age = 19
        if age >= 18:
        print("You are old enough to vote!")
        
        If the conditional test evaluates to True, Python executes the code following the if statement. If the test evaluates to False, Python ignores the code following the if statement.
      - if-else Statements
        
        take one action when a conditional test passes and a diferent action in all other cases
        
        age = 17
        if age >= 18:
        
        print("You are old enough to vote!")
        print("Have you registered to vote yet?")
        
        else:
        
        print("Sorry, you are too young to vote.")
        print("Please register to vote as soon as you turn 18!")
      - The if-elif-else Chain
        
        test more than two possible situations, and to evaluate these
        
        age = 12
        if age < 4:
        
        print("Your admission cost is $0.")
        
        elif age < 18:
        
        print("Your admission cost is $5.")
        
        else:
        
        print("Your admission cost is $10.")
        
        age = 12
        if age < 4:
        
        price = 0
        
        elif age < 18:
        
        price = 5
        
        else:
        
        price = 10
        print("Your admission cost is $" + str(price) + ".")
      - Multiple elif Blocks
        
        You can use as many elif blocks in your code as you like.
      - Omitting the else Block
        
        Python does not require an else block at the end of an if-elif chain. Some- times an else block is useful; sometimes it is clearer to use an additional elif statement that catches the specific condition of interest:
        
        age = 12
        if age < 4:
        
        price = 0
        
        elif age < 18:
        
        price = 5
        
        elif age < 65:
        
        price = 10
        
        elif age >= 65:
        
        price = 5
        
        If you have a specific final condition you are testing for, consider using a final elif block and omit the else block
      - Testing Multiple Conditions
        
        sometimes it’s important to check all of the conditions of interest
        
        This technique makes sense when more than one condi- tion could be True, and you want to act on every condition that is True
        
        requested_toppings = ['mushrooms', 'extra cheese']
        if 'mushrooms' in requested_toppings:
        
        print("Adding mushrooms.")
        
        if 'pepperoni' in requested_toppings:
        
        print("Adding pepperoni.")
        
        if 'extra cheese' in requested_toppings:
        
        print("Adding extra cheese.")
        
        print("\nFinished making your pizza!")
        =>>
        Adding mushrooms.
        Adding extra cheese.
        Finished making your pizza!
        
        if you want only one block of code to run, use an if-elif- else chain. If more than one block of code needs to run, use a series of independent if statements.
    - - watch for special values that need to be treated differently than other values in the list.
        
        Checking for Special Items
        
        how you can watch for special values in a list and handle those values appropriately.
        
        requested_toppings = ['mushrooms', 'green peppers', 'extra cheese']
        for requested_topping in requested_toppings:
        
        if requested_topping == 'green peppers':
        print("Sorry, we are out of green peppers right now.")
        else:
        print("Adding " + requested_topping + ".")
        
        print("\nFinished making your pizza!")
        =>> Adding mushrooms.
        Sorry, we are out of green peppers right now.
        Adding extra cheese.
        Finished making your pizza!
        
        Checking That a List Is Not Empty
        
        check whether a list is empty before running a for loop.
        
        requested_toppings = []
        if requested_toppings:
        
        for requested_topping in requested_toppings:
        print("Adding " + requested_topping + ".")
        print("\nFinished making your pizza!")
        else:
        print("Are you sure you want a plain pizza?")
        
        Multiple Lists
        
        use lists and if statements to make sure your input makes sense before you act on it.
        
        available_toppings = ['mushrooms', 'olives', 'green peppers', 'pepperoni', 'pineapple', 'extra cheese']
        requested_toppings = ['mushrooms', 'french fries', 'extra cheese']
        for requested_topping in requested_toppings:
        
        if requested_topping in available_toppings:
        print("Adding " + requested_topping + ".")
        
        else:
        
        print("Sorry, we don't have " + requested_topping + ".")
        
        print("\nFinished making your pizza!")
        =>> Adding mushrooms.
        Sorry, we don't have french fries.
        Adding extra cheese.
        Finished making your pizza!
- - - - A dictionary in Python is a collection of key-value pairs. Each key is connected to a value
      - A key’s value can be a number, a string, a list, or even another dictionary.
      - alien_0 = {'color': 'green', 'points': 5}
        
        wrapped in braces, {}
        
        connected to its value by a colon
        
        individual key-value pairs are sepa- rated by commas
        
        The string 'color' is a key
        
        its associated value is 'green'.
      - A key-value pair is a set of values associated with each other
      - Accessing Values in a Dictionary
        
        alien_0 = {'color': 'green'}
        print(alien_0['color'])
        =>> green
        
        alien_0 = {'color': 'green', 'points': 5}
        new_points = alien_0['points']
        print("You just earned " + str(new_points) + " points!")
        =>> You just earned 5 points!
      - Adding New Key-Value Pairs
        
        alien_0 = {'color': 'green', 'points': 5}
        print(alien_0)
        =>> {'color': 'green', 'points': 5}
        alien_0['x_position'] = 0
        alien_0['y_position'] = 25
        print(alien_0)
        =>> {'color': 'green', 'points': 5, 'y_position': 25, 'x_position': 0}
        
        the order of the key-value pairs does not match the order in which we added them.
        
        Python doesn’t care about the order in which you store each key-value pair; it cares only about the connection between each key and its value.
      - an Empty Dictionary
        
        alien_0 = {}
        alien_0['color'] = 'green'
        alien_0['points'] = 5
        print(alien_0)
        =>> {'color': 'green', 'points': 5}
        
        you’ll use empty dictionaries when storing user-supplied data in a dictionary or when you write code that generates a large number of key-value pairs automatically.
      - Modifying Values in a Dictionary
        
        alien_0 = {'color': 'green'}
        print("The alien is " + alien_0['color'] + ".")
        =>> The alien is green.
        alien_0['color'] = 'yellow'
        print("The alien is now " + alien_0['color'] + ".")
        =>> The alien is now yellow.
        
        We’ll store a value representing the alien’s current speed and then use it to determine how far to the right the alien should move:
        alien_0 = {'x_position': 0, 'y_position': 25, 'speed': 'medium'}
        print("Original x-position: " + str(alien_0['x_position']))
        =>> Original x-position: 0
        Move the alien to the right.
        Determine how far to move the alien based on its current speed.
        if alien_0['speed'] == 'slow':
        x_increment = 1
        elif alien_0['speed'] == 'medium':
        x_increment = 2
        else:
        This must be a fast alien.
        x_increment = 3
        The new position is the old position plus the increment. alien_0['x_position'] = alien_0['x_position'] + x_increment
        print("New x-position: " + str(alien_0['x_position']))
        =>> New x-position: 2
      - Removing Key-Value Pairs
        
        alien_0 = {'color': 'green', 'points': 5}
        print(alien_0)
        =>> {'color': 'green', 'points': 5}
        del alien_0['points'] print(alien_0)
        =>> {'color': 'green'}
        
        the deleted key-value pair is removed permanently.
      - A Dictionary of Similar Objects
        
        favorite_languages = {
        
        'jen': 'python',
        'sarah': 'c',
        'edward': 'ruby',
        'phil': 'python',
        }
        
        print("Sarah's favorite language is " + v favorite_languages['sarah'].title() + w ".")
        =>>> Sarah's favorite language is C.
        
        we’ve broken a larger dictionary into several lines
        
        press ENTER after the opening brace.
        
        write the first key-value pair, followed by a comma
    - - Looping Through All Key-Value Pairs
        
        user_0 = {
        
        'username': 'efermi',
        'first': 'enrico',
        'last': 'fermi',
        }
        
        for key, value in user_0.items():
        
        print("\nKey: " + key)
        print("Value: " + value)
        
        You can choose any names you want for these two variables
        
        This code would work just as well if you had used abbreviations for the variable names, like this:
        for k, v in user_0.items()
        
        the method items(), which returns a list of key-value pairs.
        
        Results:
        Key: last
        Value: fermi
        Key: first
        Value: enrico
        Key: username
        Value: efermi
        
        the key-value pairs are not returned in the order in which they were stored
        
        favorite_languages = {
        
        'jen': 'python',
        'sarah': 'c',
        'edward': 'ruby',
        'phil': 'python',
        }
        
        for name, language in favorite_languages.items():
        
        print(name.title() + "'s favorite language is " +
        language.title() + ".")
        
        Jen's favorite language is Python.
        Sarah's favorite language is C.
        Phil's favorite language is Python.
        Edward's favorite language is Ruby.
      - Looping Through All the Keys in a Dictionary
        
        for name in favorite_languages.keys():
        
        print(name.title())
        
        tells Python to pull all the keys from the dictionary favorite_languages
        
        Jen
        Sarah
        Phil
        Edward
        
        keys() method explicitly if it makes your code easier to read, or you can omit it if you wish.
        
        friends = ['phil', 'sarah']
        for name in favorite_languages.keys():
        
        print(name.title())
        if name in friends:
        print(
        " Hi " + name.title() +
        ", I see your favorite language is " +
        favorite_languages[name].title() + "!"
        )
        
        Edward Phil
        Hi Phil, I see your favorite language is Python!
        Sarah
        Hi Sarah, I see your favorite language is C!
        Jen
        
        if 'erin' not in favorite_languages.keys():
        
        print("Erin, please take our poll!")
        
        Erin, please take our poll!
      - Looping Through a Dictionary’s Keys in Order
        
        for name in sorted(favorite_languages.keys()):
        
        print(name.title() + ", thank you for taking the poll.")
        
        =>>> Edward, thank you for taking the poll.
        Jen, thank you for taking the poll.
        Phil, thank you for taking the poll.
        Sarah, thank you for taking the poll.
      - Looping Through All Values in a Dictionary
        
        print("The following languages have been mentioned:")
        for language in favorite_languages.values():
        
        print(language.title())
        
        The following languages have been mentioned:
        Python
        C
        Python
        Ruby
        
        This approach pulls all the values from the dictionary without checking for repeats
        
        print("The following languages have been mentioned:")
        for language in set(favorite_languages.values()): >>>print(language.title())
        
        The result is a nonrepetitive list of languages
        
        The following languages have been mentioned:
        Python
        C
        Ruby
    - - you’ll want to store a set of dictionaries in a list or a list of items as a value in a dictionary. This is called nesting. You can nest a set of dictionaries inside a list, a list of items inside a dictionary, or even a dictionary inside another dictionary
      - A List of Dictionaries
        
        alien_0 = {'color': 'green', 'points': 5}
        alien_1 = {'color': 'yellow', 'points': 10}
        alien_2 = {'color': 'red', 'points': 15}
        aliens = [alien_0, alien_1, alien_2]
        for alien in aliens:
        
        print(alien)
        
        =>> {'color': 'green', 'points': 5}
        {'color': 'yellow', 'points': 10}
        {'color': 'red', 'points': 15}
        
        Make an empty list for storing aliens.
        aliens = []
        we use range() to create a fleet of 30 aliens:
        for alien_number in range(30):
        
        new_alien = {'color': 'green', 'points': 5, 'speed': 'slow'}
        aliens.append(new_alien)
        
        Show the first 5 aliens:
        for alien in aliens[:5]:
        
        print(alien)
        print("...")
        
        Show how many aliens have been created.
        print("Total number of aliens: " + str(len(aliens)))
        
        {'speed': 'slow', 'color': 'green', 'points': 5}
        {'speed': 'slow', 'color': 'green', 'points': 5}
        {'speed': 'slow', 'color': 'green', 'points': 5}
        {'speed': 'slow', 'color': 'green', 'points': 5}
        {'speed': 'slow', 'color': 'green', 'points': 5}
        ...
        Total number of aliens: 30
        
        Make an empty list for storing aliens.
        aliens = []
        Make 30 green aliens.
        for alien_number in range (0,30):
        
        new_alien = {'color': 'green', 'points': 5, 'speed': 'slow'}
        aliens.append(new_alien)
        
        for alien in aliens[0:3]:
        
        if alien['color'] == 'green':
        
        alien['color'] = 'yellow'
        alien['speed'] = 'medium'
        alien['points'] = 10
        
        Show the first 5 aliens:
        for alien in aliens[0:5]:
        
        print(alien)
        
        print("...")
        
        {'speed': 'medium', 'color': 'yellow', 'points': 10}
        {'speed': 'medium', 'color': 'yellow', 'points': 10}
        {'speed': 'medium', 'color': 'yellow', 'points': 10}
        {'speed': 'slow', 'color': 'green', 'points': 5}
        {'speed': 'slow', 'color': 'green', 'points': 5}
        ...
        
        You could expand this loop by adding an elif block that turns yellow aliens into red
        
        for alien in aliens[0:3]:
        
        if alien['color'] == 'green':
        
        alien['color'] = 'yellow'
        alien['speed'] = 'medium'
        alien['points'] = 10
        
        elif alien['color'] == 'yellow':
        
        alien['color'] = 'red'
        alien['speed'] = 'fast'
        alien['points'] = 15
      - A List in a Dictionary
        
        Rather than putting a dictionary inside a list, it’s sometimes useful to put a list inside a dictionary. For example, consider how you might describe a pizza that someone is ordering.
        
        Store information about a pizza being ordered.
        pizza = {
        
        'crust': 'thick',
        'toppings': ['mushrooms', 'extra cheese'],
        }
        
        Summarize the order.
        print("You ordered a " + pizza['crust'] + "-crust pizza " +
        "with the following toppings:")
        for topping in pizza['toppings']:
        
        print("\t" + topping)
        
        You ordered a thick-crust pizza with the following toppings:
        mushrooms
        extra cheese
        
        You can nest a list inside a dictionary any time you want more than one value to be associated with a single key in a dictionary
        
        favorite_languages = {
        'jen': ['python', 'ruby'],
        'sarah': ['c'],
        'edward': ['ruby', 'go'],
        'phil': ['python', 'haskell'],
        }
        for name, languages in favorite_languages.items():
        
        print("\n" + name.title() + "'s favorite languages are:")
        
        for language in languages:
        
        print("\t" + language.title())
        
        Jen's favorite languages are:
        Python
        Ruby
        Sarah's favorite languages are:
        C
        Phil's favorite languages are:
        Python
        Haskell
        Edward's favorite languages are:
        Ruby
        Go
      - A Dictionary in a Dictionary
        
        users = {
        'aeinstein': {
        'first': 'albert',
        'last': 'einstein',
        'location': 'princeton',
        },
        'mcurie': {
        'first': 'marie',
        'last': 'curie',
        'location': 'paris',
        },
        }
        for username, user_info in users.items():
        
        print("\nUsername: " + username)
        full_name = user_info['first'] + " " + user_info['last']
        location = user_info['location']
        print("\tFull name: " + full_name.title())
        print("\tLocation: " + location.title())
        
        Username: aeinstein
        
        Full name: Albert Einstein
        Location: Princeton
        
        Username: mcurie
        
        Full name: Marie Curie
        Location: Paris